[VBprogrammer]

Web megacorps are normally allergic to any kind of human review because they are in the business of picking up pennies on each interaction via adverts. It's unsustainable to police the world on that model.

Amazon is in a different space here. Even the smoothest transaction goes through a handful of literal human hands. They have to pay for those hands regardless. At the very least following up on cases where customers (and competitors) flag fraud on their system should be possible.